Evaluation of Transport Properties of Ternary (OPC/FA/SF) Concrete Mixtures Using Migration and Absorption-Type Tests

摘要

The purpose of this study was to evaluate selected transport properties (resistance to chloride-ion penetration and rate of water absorption) of ternary concrete mixtures containing fly ash and silica fume using different test methods. The resistance to chloride-ion penetration was evaluated using two non-steady, electric field migration tests: rapid chloride permeability (RCP) (MSHTO T 277) test and rapid migration procedure (MSHTO TP 64). The rate of water absorption was evaluated using the ASTM C1585 sorptivity test and the non-standard absorptivity (ponding water absorption) test. Four mixture compositions (with varying contents of fly ash and silica fume) and five different curing conditions were used in the study. The test results were statistically analyzed (using regression method) to explore the relationships between composition, age of concrete and transport properties. In addition, the existence of possible interrelationships between the transport properties themselves was examined. For continuously moist cured specimens (Series 1 mixtures) the migration-type tests were found to be more reproducible than the absorption-based methods. However, the repeatability of absorptivity test was greatly improved if specimens were dried for certain period of time prior to testing (Series 2 mixtures). Although the curing method was found to have a very significant impact on the RCP and initial absorptivity values of all tested concrete mixtures, at later age much of the observed differences in those properties diminished.